Clinical research
VARIANT CREUTZFELDT-JAKOB DISEASE CURRENT DATA (NOVEMBER 2012)
Country UK France
R of Ireland Italy USA
Canada
Saudi Arabia Japan
Netherlands Portugal Spain
Taiwan
Total number of primary cases (number alive)
173 (0) 27 (2) 4 (0) 2 (0)
3* (0) 2 (1) 1 (0) 1**
3 (0) 2 0)
5 (0) 1 (0)
Total number of secondary cases: blood transfusion (number alive)
3 (0) - - - - - - - - - - -
REFERENCES Table 2
Residence in UK > 6 months during period 1980-1996
176 1 1
0 2 1
0 0 0 0 0 1
* The third patient with vCJD was born and raised in Saudi Arabia and has lived permanently in the United States since late 2005. According to the US case-report, the patient was most likely infected as a child living in Saudi Arabia.
** The case from Japan resided in the UK for 24 days in the period from 1980-1996. Continued »
was the first reported study in over 40 years investigating instrument decontamination in the NHS and in common with earlier work demon- strated deficiencies in a number of key areas across all sectors. A risk-based approach was taken
to reduce the likelihood of iatrogenic CJD from contaminated medical devices. Surgical instruments were classified into high, medium or low risk for vCJD, dependant on the tissues they were likely to encounter during surgical procedures (table 3). A programme of work to improve decontamination processes then followed which initially focused on interventions involving tissues containing high levels of infectivity (CNS and posterior orbit of eye) and subsequently medium risk tissues (lymphoreticular tissue), which involved major upgrades to central decontamination units. To inform the development of an
evidence-based approach to limit risks associated with dental surgery (low risk), a number of pieces of work were undertaken. The first of these was a large observational investigation into the current prac- tice of instrument decontamination against a benchmark of the BDA
Aı2 advice sheet and good practice recommendations for the decon- tamination of surgical instrumentsı6. The findings in dental practice
were in principle no different from those undertaken in sterile service departments and endoscope repro- cessing units in demonstrating several shortcomings. This led to the publication of the Health Protection Scotland (HPS) Local Decontamina- tion Unit (LDU) guidanceı7 and a series of Scottish Executive Health Department letters outlining recom- mendations for the upgrading of instrument reprocessing in dental practice (and dental hospitals). Additional elements of evidence
have been published on inadequate cleaning of first, matrix bandsı8 and then endodontic filesı9. These pieces of work perhaps sum up many of the challenges in adapting to calls to improve decontamination in dental practice in that, although this work demonstrated residual blood and tissue residues on reprocessed devices, it was not linked directly to adverse events in patients. Nevertheless, these instruments
are now single-use devices. Further risk is reduced by good decontami- nation practice and the methods
Continued »
1. Büeler H, Aguzzi A, Sailer A, Greiner RA, Autenried P, Aguet M, Weissmann C. (1993) Mice devoid of PrP are resistant to scrapie. Cell 73(3): 1339-47. 2. Manson J, Clarke A, McBride P, Aitchison L, McConnell I, Hope J (1994) PrP gene dosage determines the timing but not the final intensity or distribution of lesions in scrapie pathology. Neurodegeneration 3(4): 331-40. 3. Cuille J, Chelle P-L. (1936) Pathologie animale: la maladie dite tremblante du mouton est-elle inoculable? C R Acad Sci 203: 1552–4. 4. Beck E, Daniel P, Alpers M, Gajdusek D, Gibbs C Jr (1966) Experimental ‘kuru’ in chimpanzees. A pathological report. Lancet 2 (7472): 1056-9. 5. Gibbs CJ Jr, Gajdusek DC, Asher DM, Alpers MP, Beck E, Daniel PM, Matthews WB. (1968) Creutzfeldt-Jakob disease: transmission to the chimpanzee. Science 161(3839): 388-9. 6. Will RG, Ironside JW, Zeidler M, Cousens SN, Estibeiro K, Alperovitch A, Poser S, Pocchiari M, Hofman A, Smith PG. (1996) A new variant of Creutzfeldt-Jakob disease in the UK. Lancet 347: 921-5. 7. Bruce ME, Will RG, Ironside JW, McConnell I, Drummond D, Suttie A, McCardle L, Chree A, Hope J, Birkett C, Cousens S, Fraser H, Bostock CJ. Transmissions to mice indicate that ‘new variant’ CJD is caused by the BSE agent. (1997) Nature 1997 389: 498-501. 8. Piccardo P, Manson J, King D, Ghetti B, Barron R (2007) Accumulation of prion protein in the brain that is not associated with trans- missible disease. PNAS 104(11): 4712-7. 9. Prusiner SB (1982) Novem proteinaceous infectious particles cause scrapie. Science 216(4542): 136-44. 10. Pattison I.H. 1966 The relative susceptibility of sheep, goats and mice to two types of goat scrapie
Res.Vet.Sci. 7, 207-212 11. Barron RM, ThomsonV, Jamieson E, Melton DW, Ironside J,Will R, Manson JC (2001) Changing a single amino acid in the N-terminus of murine PrP alters TSE incubation time across three species barriers. EMBO J 20: 5070–8. 12. The Specified Bovine Offal (Amendment) Order 1995. Available at:
www.legislation.gov. uk/uksi/1995/3246/made?view=plain 13. Hewitt PE, Llewelyn CA, Mackenzie J, Will RG. Creutzfeldt-Jakob disease and blood trans- fusion: results of the UK Transfusion Medicine Epidemiology Review study. (2006) Vox Sang 91: 221-30. 14. Health Protection Agency (2012). Summary results on the second national survey of abnormal prion prevalence in archived appendix specimens. Vol 6, No. 29, 20 July 2012. 15. Scottish Executive Health Department (2001) The decontamination of surgical instru- ments and other medical devices. NHS HDL. 20 August.
www.sehd.scot.nhs.uk/publications/ dsmid/
dsimd-00.htm. 16. Scottish Executive Health Department (2004) NHS Scotland: Sterile Services Provision Review Group: survey of decon- tamination in general dental practice. 26 November.
www.scotland.gov.uk/Publi cations/2004/11/20093/45220. 17. Health Protection Scotland (HPS) (2007) Local Decontamination Units: Guidance on the requirements for equipment, facilities and management.
http://www.documents.hps.
scot.nhs.uk/hai/decontamination/publica- tions/ldu-001-02-v1-2.pdf 18. Lowe AH, Bagg J, Burke FJT, MacKenzie D, McHugh S. (2001) A study of blood contamina- tion of Siqveland matrix bands. British Dental Journal 192: 43–5. 19. Letters S, Smith AJ, McHugh S, Bagg J. (2005) A study of visual and blood contamina- tion on reprocessed endodontic files from general dental practice. British Dental Journal 199: 522–5.
Scottish Dental magazine 59
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